The present invention relates to an image forming apparatus which forms image data upon a recording medium by a method of electrophotography.
As an image forming apparatus which performs both monochrome image formation and color image formation, a composite image forming apparatus has been proposed, as for example disclosed in Japanese Laid-Open Patent Publication Heisei 08-183174 or in Japanese Laid-Open Patent Publication 2002-192708, in which, in consideration of the characteristics of each image formation method and in consideration of the circumstances of use of the color images, an image formation unit which performs monochrome image formation by a method of electrophotography and an image formation unit which performs color image formation by an ink jet method.
When a monochrome image and a color image are formed upon a single recording medium with a composite image forming apparatus according to the prior art, there is a conspicuous disparity in the image quality between the monochrome image which has been formed by the method of electrophotography and the color image which has been formed by the ink jet method, and this gives rise to a sense of discomfort with regard to the visibility of the image.
Due to this, in consideration of increase of the speed of monochrome image formation processing, and in order to create an image with which there is no sense of discomfort when mixing together a monochrome image and a color image in which individual images it has been considered to provide a monochrome image formation unit and a color image formation unit, with both of these image forming units forming images by a method of electrophotography.
However, if a monochrome image formation unit which operates by a method of electrophotography and a color image formation unit which likewise operates by a method of electrophotography are simply provided, this invites increase in size of the apparatus and substantial rise in its cost, due to increase of the number of its component parts. Moreover, the conveyance path for the recording medium becomes more complicated, and the operability with regard to the task of eliminating jamming and the like is deteriorated.
The object of the present invention is to provide an image forming apparatus which can use some members in common in both of two image formation units both of which operate by a method of electrophotography, thus making the device more compact, reducing the number of component parts, simplifying the conveyance path, and implementing enhancement of operability.